Abstract:To address the issues of poor self-stability in water-rich altered surrounding rock roadways, eccentric loading of supporting structures, and concrete perforation, research was conducted through field monitoring, analysis, and support optimization. The findings indicate that groundwater erosion is the primary cause of calcium carbonate crystal precipitation in concrete, while cavities formed by the shedding of concrete and rock walls are critical factors leading to local bending of steel arches and eccentric loading of supporting structures. Based on these insights, improvements were proposed to the original support scheme, including grouting to reduce seepage and block seepage channels in altered rock masses, laying exposed rebar and welding steel columns, spraying fiber-reinforced concrete, and performing high-pressure backfill grouting. Monitoring data reveal that after implementing the optimized support scheme, the stress distribution of the arch in altered surrounding rock significantly improved, effectively transferring partial loads from the arch to the vault. The seepage issue in the surrounding rock was successfully controlled, and the overall surface quality of the concrete markedly enhanced. This study provides a practical reference for the support design of roadway altered surrounding rock.